The reason for the three old beings to look for Skraal is simple. They are looking for groups and individuals that can do some damage to enemy races of sentient-races, as from their words it is clear that in one year's time, a big battle is going to be fought between two races. Three old beings knew that without enough help, they would have their problems with non-sentient races, or mindless beings with strong power and original power.
For these reasons, they believe that it is best for them to make some sort of a point of what they would like to see and manifest in their mind. They needed help. They needed help that may have created some sort of a difference. The power of Skraal is already high enough to make a difference in the whole battle, not to mention the fact that his abilities are highly versatile and can be used not only for combat purposes but for other purposes as well.